head to head
Neither is simply harder - they are hard in different places. A Dance of Fire and Ice demands more execution; Super Mario World demands more optimization.

Execution · Pure Mechanics
Strict one-button rhythm game where two orbiting planets must hit every beat exactly.

Execution · Pure Mechanics
Precise jump execution across fixed levels with secrets to memorise.
A Dance of Fire and Ice leans Execution (Pure Mechanics); Super Mario World leans Execution (Pure Mechanics).
A Dance of Fire and Ice leans clearly harder on execution.
A Dance of Fire and Ice
One-button precision timing with zero forgiveness
Super Mario World
Perfect inputs trivialise every jump, spin and cape flight
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
A Dance of Fire and Ice
No opponent, just the track
Super Mario World
Scripted Koopas adapt to nothing
Super Mario World leans a little harder on variance, though the gap is small.
A Dance of Fire and Ice
Completely deterministic patterns
Super Mario World
Levels are fixed; nothing hidden survives one playthrough
Super Mario World leans clearly harder on optimization.
A Dance of Fire and Ice
Learning the rhythm map is quick, executing it isn't
Super Mario World
Secret exits and route knowledge add a modest solvable layer
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.